Electrochemical Principles of Metallurgy - Lesson Summary

The principles of metallurgy are effective in the reduction of metal ions to their respective metals in their solution (or) molten states. The reduction is carried out through electrolysis (or) using reducing elements. Such methods are based on electrochemical principles.

The value of E0 for a metal depends on its reactivity. Thus, it differs from metal to metal. More reactive metals have high E0, whereas less reactive metals have low E0. It is difficult to reduce metals that have high E0.

If the difference between the E0 values of two metals is positive, then the value of ∆G0 will be negative.

Hence, the less reactive metal will come out of the solution and the more reactive metal will go into the solution.

In a simple electrolysis process, the positive ions always move towards the negative electrode called the cathode.

Precautions to be taken:

· Consider the reactivity of the metal produced in the electrolysis.

· Use suitable material as the electrodes.

· Sometimes flux is needed to increase the conductivity of the molten mass.

Metallurgy of aluminium:

Addition of cryolite and fluorspar as flux to aluminium oxide because pure aluminium oxide is a bad conductor of heat and electricity. The fused substance is used as the electrolyte.

During this process, the electrolyte is taken in a steel container lined with carbon, which acts as the cathode. A bunch of graphite rods immersed in the electrolyte act as the anode. This process is also known as the Hall-Heroult process. When current is passed, all the Al+3 ions move towards the cathode. Oxygen is liberated at the anode, which reacts with the carbon atoms of the anode to form carbon monoxide and carbon dioxide.

Cathode: Al3+ + 3e- → Al(l)

Anode : C(s) + O2- → CO(g) + 2e-C(s) + 2O2- → CO2(g) + 4e-

Generally, copper is extracted from its low concentrated ores by a process known as "hydrometallurgy". In this process, a solution containing Cu+2 ions is treated with a scrap of iron or hydrogen.

Comments(0)

The Next Learning Center(NLC), launched by Next Education in Hyderabad, is an innovative after-school program that lets children have a personalized learning experience outside the domain of formal education system.

Enroll and get attractive discounts on tuition and activity classes at NLC!